Check engine light on
 

I have a 2006 5.3 Silverado with 154000+ miles, about a month ago my check engine light came on and according to the mechanic it was the knock sensor so he recommended replacing both, which he did. Now my check engine light came on again. Anyone have any suggestions? The mechanic says the reader shows knock sensors again. Can it be something else? I haven't got a diagnostic check done.

What is the code that you are getting. Autozone and Advance Auto parts will put their scanner on and read the code for you for free.

I didn't get that info from the mechanic. I asked him and he said it could be a couple of things , sensors or even the computer module. he suggested a diagnostic, which I have already set up an appointment for next week. I am curios if anyone else has gone through this process of a mechanic just saying it was knock sensors and then being something else.

I just had a diagnostic test done. Dealership says its the knock sensor harness because it's moving and giving different ohms readings, and the pcm has bad modules. Total cost to repair is 1500 for new oem knock sensors and harness as well as a new pcm. It seems pretty steep since the total of all parts is only 500. Any suggestions?

ks harness replaced
 

Well I just replaced my knock sensor harness and rechecked the knock sensors and they checked out fine, Now after driving the truck for one day the check engine light has returned, Anyone have any suggestions on replacing my pcm, or do I just need to take it to the dealership and have them do it?

Hi mibar,

I'm sorry to hear that your Check Engine Light has returned. I understand that you are seeking opinions from the other forum members in regard to your concern. If you decide to go the dealership route feel free to let us know. If needed, we can contact your dealer on your behalf to discuss your concern with them. We'd be happy to help!

Kristen A.
Chevrolet Customer Care

if the pcm has bad modules it needs to be replaced and reprogrammed by the dealer. you could find a pcm online and install it then tow it to a dealer to have it programed

I have found an auto engineering mechanic in town that says he will program it for 125.00. I haven't got a quote from the dealer yet.

Not trying to be a dick here but, have any of these mechanics checked for a legitimate reason for that sensor to register, as in a legitimate knock issue caused by incorrect timing, poor fuel quality, compression fault or any one of the various things the computer says is incorrect information coming from it.

I'm sorry, I am much quicker to believe that there is an issue within the motor it self after a hundred and fifty thousand miles than a PCM failure, (BTW, I have experienced PCM failure).

I agree, that is a very valid point, it could very well be detecting a knock...
might try a different grade of fuel and getting it from a different station as an easy place to start.